Key assessment

Past trends

Direct observations of the effects of recent climate change on competition are scarce and are generally thought not to have led directly to the extinction of species in Europe [i]. However, independent studies have shown that observed changes in the distribution and abundance of Populus species (a group of trees that are relatively weak competitors) in the Late Glacial (ca. 13 000–10 000 years ago) and in the 20th century could only be explained when the effects of climate change on its competitors were taken into account [ii].

Climate change has already lead to temporal mismatches between species that depend on each other for feeding and for pollination. For example, the egg hatch of the winter moth (Operophtera brumata) has advanced more than the budburst date of its larval food plant, the pedunculate oak (Quercus robur), over the past two decades, with potentially severe consequences for its fitness [iii]. Similarly, over the last 30 years, the occurrence of the honey bee (Apis mellifera) and the Small White butterfly (Pieris rapae) in relation to the flowering of crucial host plants has changed from about 10 days and 5 days later to about 25 days and 15 days earlier, respectively [iv]. Such temporal mismatches can severely impact pollination activities and the seed set of plants [v]. Climate change has also disrupted several predator-prey relationships, such as between insectivorous birds and their insect prey [vi]. In some cases, differential changes in phenology can also strengthen existing or create new predator-prey relationships, as observed by an increased predation pressure of the fat dormouse (Glis glis) on several songbirds in the Czech Republic [vii].

Climate change can also generate new interactions in novel communities [viii]. In extreme cases, this can lead to severely transformed ecosystems where new species dominate. Such changes are particularly obvious at higher latitudes and altitudes, where growing and reproductive periods are prolonged or where previous thermal constraints are released with climate warming. For instance, the range of the pine processionary moth (Thaumetopoea pityocampa) is no longer limited by temperature in many regions, enabling the species to expand its existing range into new areas and causing serious damage in pine forests [ix].

Projections

A study on butterflies in Europe showed that most species are not limited by the distribution of their larval host plants and thus appear rather insensitive to spatial mismatching with their hosts under future climate change. However, there are exceptions such as the Portuguese Dappled White butterfly (Euchloe tagis), which is projected to lose 20–48 % of its current area based on the loss of suitable climatic conditions by 2080, and 50–74 % when a reduced availability of host plants was also considered (Figure 1) [x]. These findings highlight the need for a better understanding of ecological interactions that mediate species responses to climate change.

Data sources

Justification for indicator selection

The impacts of climate change on single species can lead to disruptions or alterations of currently existing species interactions such as competition, herbivory, predation, parasitism, pollination and symbiosis. These interactions are affected because different species adapt their phenology (i.e. the timing of annual events) and their distributional range differently in response to climate change. Climate change can also affect disturbance regimes, such as wildfires and storms. These higher-level biodiversity impacts are of particular importance since biodiversity, besides being realised as a value in its own right, is increasingly acknowledged as providing indispensable ecosystems services for human well-being. Biodiversity can be regarded as ‘our collective life insurance’, as noted in the ‘EU biodiversity strategy to 2020’.

An improved understanding of how climate change will affect species interactions in novel communities established under a novel climate can be utilised to assess the extinction risk of species of particular conservation concern. It will also enhance our abilities to assess and mitigate potential negative effects on ecosystem functions and services. Despite increasing knowledge about effects of climate change on pairwise species interactions and on complete ecological networks, quantitative assessments of these effects are still very uncertain.

Scientific references:

No rationale references
available

Policy context and targets

Context description

In April 2013 the European Commission presented the EU Adaptation Strategy Package (http://ec.europa.eu/clima/policies/adaptation/what/documentation_en.htm). This package consists of the EU Strategy on adaptation to climate change /* COM/2013/0216 final */ and a number of supporting documents. One of the objectives of the EU Adaptation Strategy is Better informed decision-making, which should occur through Bridging the knowledge gap and Further developing Climate-ADAPT as the ‘one-stop shop’ for adaptation information in Europe. Further objectives include Promoting action by Member States and Climate-proofing EU action: promoting adaptation in key vulnerable sectors. Many EU Member States have already taken action, such as by adopting national adaptation strategies, and several have also prepared action plans on climate change adaptation.

The European Commission and the European Environment Agency have developed the European Climate Adaptation Platform (Climate-ADAPT, http://climate-adapt.eea.europa.eu/) to share knowledge on observed and projected climate change and its impacts on environmental and social systems and on human health; on relevant research; on EU, national and subnational adaptation strategies and plans; and on adaptation case studies.

Adaptation means anticipating the adverse effects of climate change and taking appropriate action to prevent or minimise the damage they can cause, or taking advantage of opportunities that may arise. It has been shown that well planned, early adaptation action saves money and lives later. This webportal provides information on all adaptation activities of the European Commission.

In April 2013 the European Commission adopted an EU strategy on adaptation to climate change which has been welcomed by the EU Member States. The strategy aims to make Europe more climate-resilient. By taking a coherent approach and providing for improved coordination, it will enhance the preparedness and capacity of all governance levels to respond to the impacts of climate change.

Methodology

Methodology for indicator calculation

Ecological niche models (generalized linear models) for 36 European butterfly species and their larval host plants based on climate and land-use data were developed. The future distributional changes using three integrated global change scenarios for 2080 were projected. Observed and projected mismatches in potential butterfly niche space and the niche space of their hosts were first used to assess changing range limitations due to interacting species and then to investigate the importance of different ecological characteristics.

Methodology for gap filling

Not applicable

Methodology references

No methodology references available.

Uncertainties

Methodology uncertainty

Not applicable

Data sets uncertainty

Available methods for incorporating species interactions, population dynamics and dispersal processes into models of range shifts are still very coarse, despite several recent approaches to incorporate these.